Ensemble Characteristics of the Human Visual Evoked Response: Periodic and Random Stimulation

Most investigations of visual evoked potentials monitored at the human scalp have utilized the average of a series of responses recorded from a single subject in a specific population to define components of the visual evoked response (VER). While this technique provides a fairly consistent estimate of an individual´s average VER, it is not uncommon to obtain quite dissimilar averages from different subjects under identical experimental conditions. This contrast in the VER estimates across a population has hindered the interpretation of the effects of stimulus parameters on the VER and frustrated the attempt to use this average for clinical diagnosis.